Clunking rear Airlift bags

[lukey86]

So I installed a set of Airlift umm air-overs I guess you call them...theyre not bad however I'm experiencing a loud clunking noise in the rear end. The kind of noise you would hear if you half loosened the top hat nuts and then drove on a bumpy road, a very loud ca-clunk!

Before the air I had coilovers on the car for ages and never heard anything like it so I know its something to do with the new airlift gear. Everything has been double and triple checked for tightness and no change, the only thing I can think of is bad pillow ball joints but it seems weird that both of them would be like this.

Any ideas? and is there anyone out there on bags who has had a similar experience??

[Vroomin86]

Dude I am having the exact same issue. Sounds more like from the drivers side rear

Also lets see how similar our issues are, mine only happens when I am at high PSI. Have you tried driving around about 25 psi front and 45 psi rear. Does it still do it?

[lukey86]

Yeah same! I dropped it lower yesterday and it didn't do it, but it scrubs if it's too low 😕. At least I know I'm not the only one lol tried contacting airlift about it but haven't heard back, but if we're both having the same issue then it must be common enough that they'd be aware of it and should know what it is


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[Jyn]

What stiffness on the dampers? Sounds like maybe pillow ball joint or something.

[dito]

Too much psi in the bags. Try lowering it. Mine are around 42-45- range in the rear. Any more than 49+ it starts thumping

[lukey86]

Played around with it today, its not the bag itself, the sound is coming from one of the other parts, possibly the swaybar. Ill have a closer look tomorrow, if I have to i'll remove parts one by one until i can identify the problem. If I lower the psi it doesn't do it as much but still does it over hard bumps but i can't leave it that low as my wheels scrub and thats half the reason why I got the bags lol so i'll investigate and update on the cause of the issue

[lukey86]

So with the rear end set at 80 psi I removed the wheel and and placed a jack-stand under the hub and had a friend jump up and down in the boot. After a couple of minutes of listening I concluded that the sound was coming from the shock itself. I removed it and inspected the pillow ball as that was the likely culprit but it seemed ok. I was at a loss. And then, just for the hell of it, I placed one end of the shock on the ground and pushed down on the other end and compressed it. Then I let it go. As with any damper the gas forced the piston back to it's original position but as it did so I heard a loud metallic 'pop!' as the piston hit the end of the damper tube

So no internal bump-stop. When mounted on the car the sound is amplified by the body and other suspension components. This also explains why it stops happening below a certain psi level. as the pressure is lowered the piston is moved less violently and stops hitting the end of the tube with force. I'm not sure if this is a factory defect or not but short of rebuilding the damper and including bumpstops, thres no fix. Just have to put up with it I guess...

[Vroomin86]

Originally Posted by lukey86

So with the rear end set at 80 psi I removed the wheel and and placed a jack-stand under the hub and had a friend jump up and down in the boot. After a couple of minutes of listening I concluded that the sound was coming from the shock itself. I removed it and inspected the pillow ball as that was the likely culprit but it seemed ok. I was at a loss. And then, just for the hell of it, I placed one end of the shock on the ground and pushed down on the other end and compressed it. Then I let it go. As with any damper the gas forced the piston back to it's original position but as it did so I heard a loud metallic 'pop!' as the piston hit the end of the damper tube

So no internal bump-stop. When mounted on the car the sound is amplified by the body and other suspension components. This also explains why it stops happening below a certain psi level. as the pressure is lowered the piston is moved less violently and stops hitting the end of the tube with force. I'm not sure if this is a factory defect or not but short of rebuilding the damper and including bumpstops, thres no fix. Just have to put up with it I guess...

Man that's so shitty to hear. Have you called airlift with your new findings to see if perhaps it's a bad part?

Like you said at lower PSI mine also is much more tolerable but still sucks. I wonder if other bag systems also make this noise at high PSI

[Vroomin86]

Originally Posted by Jyn

What stiffness on the dampers? Sounds like maybe pillow ball joint or something.

It intrigues me that you ask this. I hardened the tears to as much as possible and it also helped.


Here's a scenario that I still can't seem to grasp my head around.


The night I left the install shop my trunk was full (New setup, compressors, tank, all 4 Coilovers etc. point is it was very heavy) I drove home at a high psi for Atleast 24 miles and the noise didn't happen once. The next morning after removing everything and trunk being much lighter the noises started.

[lukey86]

Originally Posted by Vroomin86

Man that's so shitty to hear. Have you called airlift with your new findings to see if perhaps it's a bad part?

Like you said at lower PSI mine also is much more tolerable but still sucks. I wonder if other bag systems also make this noise at high PSI

Originally Posted by Vroomin86

It intrigues me that you ask this. I hardened the tears to as much as possible and it also helped.


Here's a scenario that I still can't seem to grasp my head around.


The night I left the install shop my trunk was full (New setup, compressors, tank, all 4 Coilovers etc. point is it was very heavy) I drove home at a high psi for Atleast 24 miles and the noise didn't happen once. The next morning after removing everything and trunk being much lighter the noises started.

I'll give airlift a call and see what they say. I just didn't wanna let myself believe that there could be such a basic defect in a product I paid so much for.

As for your full trunk, I think it actually helps to confirm my theory. When you hit a bump the suspension compresses and the high pressure in the bags makes them spring back very violently causing the damper piston to smash into the end of the tube....with a heavy load in the trunk your actually helping to absorb some of the energy contained in the compressed bags as they spring back. The weight is essentially acting as extra damping power causing the bag to return slower and therefore the piston also returns slower and doesn't smash into the end of the tube!

Now that i've said that I'm thinking we should all fill our spare tyre cavities with led!

[Vroomin86]

Originally Posted by lukey86

I'll give airlift a call and see what they say. I just didn't wanna let myself believe that there could be such a basic defect in a product I paid so much for.

As for your full trunk, I think it actually helps to confirm my theory. When you hit a bump the suspension compresses and the high pressure in the bags makes them spring back very violently causing the damper piston to smash into the end of the tube....with a heavy load in the trunk your actually helping to absorb some of the energy contained in the compressed bags as they spring back. The weight is essentially acting as extra damping power causing the bag to return slower and therefore the piston also returns slower and doesn't smash into the end of the tube!

Now that i've said that I'm thinking we should all fill our spare tyre cavities with led!

Damn it. That makes perfect sense but for nearly $3K that's a bullshit design. Let me know what you come up with when you talk to airlift. I wish more airlift owners would chime in here to see if they are having the same issue. It seems me and you bought our systems around the same time. I hope it wasn't a bad batch.

[Vroomin86]

Originally Posted by lukey86

I'll give airlift a call and see what they say. I just didn't wanna let myself believe that there could be such a basic defect in a product I paid so much for.

As for your full trunk, I think it actually helps to confirm my theory. When you hit a bump the suspension compresses and the high pressure in the bags makes them spring back very violently causing the damper piston to smash into the end of the tube....with a heavy load in the trunk your actually helping to absorb some of the energy contained in the compressed bags as they spring back. The weight is essentially acting as extra damping power causing the bag to return slower and therefore the piston also returns slower and doesn't smash into the end of the tube!

Now that i've said that I'm thinking we should all fill our spare tyre cavities with led!

Any update ?

[lukey86]

Originally Posted by Vroomin86

Any update ?

I've e-mailed them with no reply. I'll have to call, it's just a bit of a pain because i'm in Australia. Damn time zones lol

[wtfrs]

Originally Posted by lukey86

I've e-mailed them with no reply. I'll have to call, it's just a bit of a pain because i'm in Australia. Damn time zones lol

I had the same issue but yeah you just need to run a lower PSI and sacrifice how low you can go when you air out. My rear on stock wheels i can run up to 52 PSI and be perfect with no clunking.

Question for you guys, do you guys hear popping in the front when you air up? I heard its common on double bellow but just want to make sure.